Field of the Invention
The present invention relates to an aircraft safety device used for explosion-proofing a fuel tank.
Description of the Related Art
Fuel supplied to the engine of an aircraft is stored inside a main wing which doubles as a fuel tank.
Inside the main wing, a ventilation passage which leads to the outside air is provided. Ventilation through this ventilation passage provides a balance between the outside air pressure and the pressure inside the main wing.
Here, an inflammable gas, which is a mixture of air and vapor of vaporized fuel, is present inside the ventilation passage and near a ventilation port facing the outside air. In order to prevent this gas from being ignited by a lightning strike, a semi-shield is sometimes provided which shields the ventilation port from ignition sources such as sparks while allowing entry and exit of gas.
A lightning-protection fastener equipped with an insulative cap is used for explosion-proofing a fuel tank of an aircraft (Japanese Patent Laid-Open No. 2011-102122).
Ignition of an inflammable gas can also occur due to fires in airport buildings, other aircraft fires and the like, other than lightning.
In the event of ignition, it is necessary to block the flame from penetrating into the fuel tank through the ventilation passage.
If the flame is retained at the ventilation port, it is further necessary to prevent the fuel inside the fuel tank from being heated with the flame as a heat source and igniting inside the fuel tank.
The object of the present invention is to provide an aircraft safety device which can reliably prevent explosion of a fuel tank even if an inflammable gas is ignited.